Blocking element of short wavelengths in led-type light sources

ABSTRACT

Method, product and blocking element of short wavelengths in LED-type light sources consisting of a substrate with a pigment distributed on its surface and, in that said pigment has an optical density such that it allows the selective absorption of short wavelengths between 380 nm and 500 nm in a range between 1 and 99%.

FIELD OF THE INVENTION

In general, the present invention falls within the field of optics and,in particular, relates to a blocking element of short wavelengths inLED-type light sources (light-emitter diodes).

STATE OF THE ART

The electromagnetic spectrum (EME) is the energy distribution of thewhole of the electromagnetic waves that a substance emits (emissionspectrum) or absorbs (absorption spectrum). The EME includes a widerange of radiation, from that of lower wavelength such as gamma rays andx-rays, passing through ultraviolet radiation, light and infrared rays,to the electromagnetic waves with longer wavelength, such as radiowaves.

The light spectrum is the region of the electromagnetic spectrum thathuman eye is able to perceive. Electromagnetic radiation in this rangeof wavelengths is also called ‘visible’ or simply light. There are noexact limits in the visible spectrum; a typical human eye responds towavelengths from 380 nm to 780 nm, although the eye adapted to the darkcan see over a greater range, ranging from 360 nm to 830 nm.

The retina auto-protects itself from the short wavelengths in two ways:with a heterogeneous distribution of the photo-receptors in such a waythat photo-receptors, sensitive to the short wavelengths, do not existin the macular depression and by the action of yellow pigments existingin the same area that also perform a protective action. In addition, thecrystalline increases its proportion of yellow chromophores with age.

These natural protections of the human eye against the shortestwavelengths (the crystalline and those of the retina) can findthemselves seriously affected by certain pathologies and/or surgicalinterventions, even exclusively over time.

Some techniques have been developed to protect healthy eyes, cataractoperated eyes, and eyes in neuro-degenerative retina process from shortwavelengths:

-   -   Apply filters to the human eyes as a therapeutic and preventive        measure to substitute and/or improve the natural protection.    -   Since the middle of the 90's, intraocular lenses provided with a        yellow filter have been implanted on cataract operated eyes.        This alternative involves a surgical procedure with all its        obvious risks and difficulties. There also exists a large number        of people operated from cataracts to which a transparent        intraocular lens has been implanted to substitute the inner        substance of the crystalline that does not have the necessary        yellow pigmentation protection. In these cases, it is necessary        to complement the artificial crystalline, which is exempt of        yellow pigmentation, with the insertion of a yellow pigmentation        support system.

A blocking element of the short wavelengths is a device designed toseparate, pass or delete a group of objects or things of the totalmixture. The blocking elements are designed for the selection of aparticular range of wavelengths of light. The mechanism is alwayssubtractive, consists of blocking of wavelengths, allowing the passageof other wavelengths.

There are different types of filters applied to the human eye on themarket. For instance, the patent application WO 98/44380 describes afilter applied in a contact lens that does not cover the whole of saidcontact lens, understanding the whole as iris area, pupil area and thecontact lens body, this fact being fundamental for avoidingirregularities in vision. On the other hand, the document WO 91/04717describes intraocular lenses for treating of AMD which is not the objectof the present invention.

It is also known the fact of using yellow filters in ophthalmic lenses,for example through the document GB 1 480 492.

The yellow filter can be used in multiple applications, as shown by thedocuments located in the current state of the art.

The document DE 358 948 describes a yellow filter applied to anelectrical lighting device, but combined with a second red-coloredfilter, which moves away from the inventive concept described in thepresent invention.

The document ES 1 046 793 U describes an external support device ofdifferent lighting filters, with different colors, which moves away fromthe inventive concept of the present invention which lies in a uniqueblocking element of short wavelengths, integrated in a given material,to eliminate the short wavelengths from the visible light spectrumbefore it reaches the user due to pernicious effects produced by thehigh energy of this light range, aim that, evidently, is not achievedwith this document.

The document WO 90/05321 describes a filter with a series of technicalfeatures but that absolutely defines a pathophysiological applicationand in addition, the filter described in the patent application WO90/05321 is not homogeneous in its absorbance and may produce unwantedeffects.

Dr. Celia Sanchez-Ramos is the inventor of the patents ES2247946,ES2257976, ES2281301, ES2281303, ES2289957, ES2296552, ES2298089,ES2303484 and ES2312284. However, although these documents are referredto the issue of ambient light, especially the short wavelengths on thespectrum from 380 to 500 nm, none of these documents explains theproblem derived from the mass and daily use of screens primarily basedon LED technology in its different variants, like OLED, LCD-LED, AMOLED,among other cutting-edge technologies for smartphones, electronictablets, laptops and televisions, projectors and in general any screenwith LED technology and/or LED backlight.

A practical example of this type of LED technology displays is indocument US20120162156 of Apple Inc., which describes how it isinternally that known commercially as Retina® display and implemented invarious products marketed by Apple, as the MacBook Pro®, iPad® 2, oriPhone® 5. Although said document describes extensively how it isemitted the light by the LEDs (more specifically, those known as organicLEDs or OLED), at no time the presence of any medium or element to limitradiation emitted to the user of the device is considered.

FIG. 1 shows the different graphs of emission for products currentlymarketed within the visible range.

It is clear that today any particular user spends an average of 4-8hours a day, or more, in front of LED-type displays, i.e. receiving anemission of short wavelengths at a usually very small distance (on theorder of 30-50 cm), which negatively affects the eye and human vision.This problem is described in the state of the art in [Behar-Cohen et al.‘Light-emitting diodes (LED) for domestic lighting: Any risks for theeye?’ Progress in Retinal and Eye Research 30 (2011) 239-257].

Said document, in the conclusions thereof, emphasizes the need toevaluate the potential toxicity of the light emitted by the LEDs,depending on the various devices available on the market so thatefficient recommendations can be made to the domestic lightmanufacturers, due to the increased presence of LED-type lighting forindoor environments. However, this document does not commit to asolution to combine the evolution of the LED technique with a risk-freeeveryday use. That is, this document advocates, directly, the limitationand legal regulation of light emissions, without proposing any kind ofsolution for the already marketed products.

Another document that describes the associated problems in [Cajochen etal. ‘Evening exposure to a light-emitting diodes (LED)-backlightcomputer screen affects circadian physiology and cognitive performance’,Journal of Applied Physiology 110: 1432-1438, 2011, first published 17Mar. 2011] where the need to adapt the light emission to the sleep cycleis described.

This document, however, indicates that the potential toxicity of theLED-type displays is unknown and that, in any case, their associatedproblems can be reduced by reducing the light intensity.

The technical problem that underlies is the reduction of risk in the eyedamage due to the intensive use of LED-type displays. From the documentby Behar-Cohen, it is known to which type of damages the human eye isexposed, but in its conclusions, the most obvious way is used, which isto limit the use of that type of screens and force manufacturers, in ageneric way, to restrict their emissions within a specific range.However, it leaves unanswered precisely how to reduce this type ofemissions in the simplest way as possible, not only at the manufacturingstep, which is not always possible, easy or simple, but also with theproducts currently existing on the market.

DESCRIPTION OF THE INVENTION

On the basis of the technical problem described, and with the aim thatthe blocking element of emissions object of the invention does not haveto be the same in all cases and also has to be easy to implement by anyuser and not only by experts.

To provide a solution to the technical problem in an aspect of theinvention, the blocking element of short wavelengths in LED-type lightsources characterized in that it consists of a substrate with a pigmentdistributed on its surface, and in that said pigment has an opticaldensity such that it allows the selective absorption of shortwavelengths between 380 nm and 500 nm in a range between 1 and 99%.

The blocking element, in a particular embodiment is constituted by amultilayer substrate wherein at least one of said layers contains theblocking pigment of short wavelengths distributed over the surface ofsaid layer.

In another embodiment, in the blocking element of short wavelengths, thesubstrate is a coating containing a pigment in the entire coating.

In another embodiment, the coating is one selected from gel, foam,emulsion, solution, dilution or a combination of the above.

In another aspect of the invention, the blocking method of shortwavelengths in LED-type light sources is characterized in that itcomprises the steps of: (i) selecting the mean optical density of apigment, and (ii) pigmenting a substrate over its entire surface in sucha way that the mean absorbance is between 1% and 99% in the range ofshort wavelengths between 380 nm and 500 nm.

The selection of the optical density is based on at least one of thefollowing parameters: age of a user of LED-type light source, separationdistance to the LED-type light source, size of the LED-type lightsource, exposure time to the light source by the user, ambient lightingof the place where the user interacts with the LED-type light source thetype of device, the emission intensity, and the possible retinal and/orcorneal disease state.

In a particular embodiment of the element or method, the pigment isevenly distributed over the surface of the substrate.

In another aspect of the invention, the LED display comprises theblocking element of short wavelengths according to the above descriptionand/or obtained by a manufacturing process comprising a step of reducingthe emission of short wavelengths between 380-500 nm of the LEDscontained in the display. That is, the LED display with the blockingelement or default so that it contains the essential characteristics ofsaid blocking element.

In another aspect of the invention, the computer-implemented method ofblocking the short wavelengths in LED-type light sources characterizedin that it comprises the steps of: (i) calculating the emissions ofharmful short wavelengths between 380 and 500 nm; and (ii) selectivelyreducing the emission of short wavelengths between 380-500 nm of theLEDs contained in at least a part of the display, based on thecalculation set out in the previous step.

The modification on the display can be total (in the entire display) orin a part, since on certain occasions it may be necessary to maintainthe pure color in certain parts, e.g. in design graphic applications orsimilar.

As in the previous case, the calculation of the harmful emissions is afunction of at least one of the following variables: age of a user ofLED-type light source, separation distance to the LED-type light source,size of the LED-type light source, exposure time to the light source bythe user, ambient lighting of the place where the user interacts withthe LED-type light source the type of device, the emission intensity andthe possible retinal and/or corneal disease state.

In a particular embodiment, the computer-implemented method comprises afurther step of detecting the background of an electronic documentviewed by a user and a second step of switching said background to onewith a reduced emission on the spectrum between 380-500 nm.

In another aspect of the invention, the portable electronic devicecomprises a LED display; one or more processors, a memory; and one ormore programs wherein the program(s) are stored in the memory andconfigured to be executed by at least the processor(s), the programsincluding instructions for calculating the emissions of harmful shortwavelengths between 380 and 500 nm; and selectively reducing theemission of short wavelengths between 380-500 nm of at least a part ofthe LEDs contained in the display.

As in the computer-implemented method, it is possible to reduce viasoftware a part of the LEDs contained in the display.

The selective reduction is carried out by modifying the colors in theoperating system in a practical embodiment of the device.

In another practical embodiment of the device, the selective reductionis temporarily progressive depending on the exposure time of the userand the time of day.

In one final aspect of the computer program product with instructionsconfigured for execution by one or more processors that, when running,carry out the method according to the computer-implemented method.

In all aspects of the invention is equally achieve the protection of theretina, cornea and crystalline of the harmful action of the shortwavelengths, as well as eliminate the eyestrain, improve the comfort andvisual function, final objects of the invention, since this damage ineye not properly protected is a cumulative and irreversible damage.

Throughout the description and claims, the word ‘comprises’ and itsvariations are not intended to exclude other technical features,additives, components or steps. For those skilled in the art, otherobjects, advantages and characteristics of the invention will emerge inpart from the description and in part from the practice of theinvention. The following examples and drawings are provided by way ofillustration and are not intended to be limiting of the presentinvention. Furthermore, the present invention covers all the possiblecombinations of particular and preferred embodiments herein indicated.

BRIEF DESCRIPTION OF THE DRAWINGS

Described very briefly hereinafter are a series of drawings that help tobetter understand the invention, and which are expressly related to anembodiment of said invention that is presented as a non-limiting examplethereof.

FIG. 1 shows different graphs of emissions for commercial electronicproducts with LED-type display.

FIG. 2 shows the selective absorbance of the blocking element of shortwavelengths of the present invention for three examples of people ofdifferent age: 25 years old (FIG. 2a ), 45 years old (FIG. 2b ) and 76years old (FIG. 2c ).

FIG. 3 shows a view of the LED-type light source used for the examplethat illustrates the present invention. A. Schematic representation ofthe lighting device without and with the blocking element of shortwavelengths used. B. Spectral emission curves of each of the used LEDs.C. Design of the well plate where the cells were seeded.

FIG. 4 shows a graph with the LED light effect and the photoprotectiveeffect of a blocking element that selectively absorbs the shortwavelengths on the cell viability, indicative of cell survival in humanretinal pigment epithelial cells.

FIG. 5 shows the LED light effect and the photoprotective effect of ablocking element that selectively absorbs the short wavelengths on theactivation of the human histone H2AX, indicative of DNA damage in humanretinal pigment epithelial cells.

FIG. 6 shows the LED light effect and photoprotective effect of ablocking element that selectively absorbs the short wavelengths on theactivation of the caspase-3, -7, indicative of apoptosis in humanretinal pigment epithelial cells.

FIG. 7 shows a schema of a portable electronic device as that used inthe present invention.

FIGS. 8A-8D show the graphs of results of the light characterizationtest for the model Asus Memo Pad Smart.

FIGS. 9A-9D show the graphs of results of the light characterizationtest for the model Apple iPad 4.

FIGS. 10A-10D show the graphs of results of the light characterizationtest for the model Samsung Galaxy Tab 10.1.

DETAILED DESCRIPTION OF THE INVENTION AND EXAMPLE

In the state of the art the degree of toxicity of the short wavelengths,produced by LED light of different spectral composition, due to the useof an electronic device equipped with this type of displays (LED) onretinal pigment epithelial cells, has not been described.

The specific objectives of the toxicity test and the provided solutionare as follows:

Study the cell viability of the retinal tissue in vitro after exposureto different LEDs that emit radiation of different spectral composition,as shown in FIG. 4.

Assess the DNA damage of the retinal tissue in vitro after exposure todifferent LEDs that emit radiation of different spectral composition, asshown in FIG. 5.

Determine the apoptosis of the retinal tissue in vitro after exposure todifferent LEDs that emit radiation of different spectral composition, asshown in FIG. 6.

Following the assessment and determination of toxicity, the solutionsproposed in the present invention are assessed.

TABLE 1 Reagent/Equipment and Catalogue and lot Numbers Supplier HumanRetinal Pigment Epithelial cell #P10873- Sciencell Poly-L-lysine # P4707Lot No BCBC0503 Sigma Aldrich Epithelial cell medium #960106 SciencellTMRM #668 Invitrogen CM-H2DCFDA #C6827 Invitrogen Rabbit anti caspase3antibody #9661 Lot No P42574 Cell Signalling Mouse anti H2AX antibody#ab22551 Lot No 820115 Abcam Goat anti-rabbit antibody Alexa 594 #A11012Invitrogen Lot No 695244 Goat anti-mouse antibody Alexa 633 #A21050Invitrogen Lot No 690316 96well, black clear Imaging Plate #353219Becton Dickinson Bovine serum albumin #A2153 Sigma Paraformaldehyde#16005 Sigma BD Pathway 855 Becton Dickinson Hydrogen Peroxide Sol. 3%.Lot D401A

In table 1, a summary of the reagents, equipment and supplied materialused in the study is found. On the other hand, a lighting device hasbeen designed comprising five differentiated lighting zones separatedoff from each other by discriminating barriers of a white material. Eachone of the zones contains a LED producing light of irradiance 5 mW/cm²but emitting light with different spectral composition:

-   -   Blue LED (468 nm)    -   Green LED (525 nm)    -   Red LED (616 nm)    -   White LED; Color T°=5400° K

In FIG. 2A, Example 1 is a 25-year old person that uses a computer forless than three hours a day in high ambient high conditions, Example 2is a 25-year old person that uses various electronic devices(computer+table+smartphone) for more than 10 hours a day in low and highlighting environments, and Example 3 is a 25-year old person that has amoderate retinal disease state and watches TV for three to five hours aday under high lighting conditions.

In FIG. 2B, Example 1 is a 45-year old person that uses a computer forless than three hours a day in high ambient high conditions, Example 2is a 45-year old person that uses various electronic devices(computer+table+smartphone) for more than 10 hours a day in low and highlighting environments, and Example 3 is a 45-year old person that has amoderate retinal disease state and watches TV for three to five hours aday under high lighting conditions.

In FIG. 2C, Example 1 is a 76-year old person that uses a computer forless than three hours a day in high ambient high conditions, Example 2is a 76-year old person that uses various electronic devices(computer+table+smartphone) for more than 10 hours a day in low and highlighting environments, and Example 3 is a 76-year old person that has amoderate retinal disease state and watches TV for three to five hours aday under high lighting conditions.

FIG. 3 represents schematically the lighting device used and thespectral emission curves of each of the LEDs. This device was placed onthe culture plate, and the cells were exposed to LED light for 3light-dark cycles (12 hours/12 hours) with and without the interpositionof the blocking element of short wavelengths. As shown, there is a zonenot illuminated by LEDs where the cells not exposed to light which wereused as negative control are placed.

In this non-limitative, particular embodiment, the blocking element isdefined as a blocking element of short wavelengths consisting of asubstrate with a yellow pigment evenly distributed on its surface and,in that said pigment has an optical density such that it allows theselective absorption of short wavelengths between 380 nm and 500 nm in arange between 1 and 99%. More specifically, it is a film or multilayerfilm, where one of them is pigmented.

Cell Culture and Plate Design

The retinal pigment epithelial cells (RPE) were thawed following thesupplier's instructions, in ‘Epithelial cell culture medium’,supplemented with fetal bovine serum (FBS) and growth factors. At 72hours and once the culture reaches the confluence, the cells were raisedwith trypsin-EDTA and were seeded at a density of 5000 cells/well in a96-well plate previously treated with poly-lysine. The culture was keptfor 24 hours after which the medium was replaced by fresh medium (300μl/well). This procedure was repeated each of the days in which theexperiment was carried out to avoid evaporations by the heat produced bythe lamps. The plate with the lighting device was placed within theincubator at 37° C. in an atmosphere of 5% CO₂.

The toxicity experiment was conducted after the cells were incubated inthe presence of light of different spectral characteristics for 3exposure/rest cycles of 12 hours per cycle.

The samples were washed with PBS and fixed with 4% paraformaldehyde for15 minutes. After fixation, the cells were permeated with 0.3% Tritonfor 10 minutes. Once the samples were permeated, they were blocked with5% BSA and the anti-caspase and anti-H2AX antibodies dissolved in 2.5%PBS+BSA were then added at a concentration of 1:400 for thedetermination of apoptosis and DNA damage respectively.

After an hour of incubation, the samples were washed with PBS, andsecondary antibodies, Alexa 594 and Alexa 633, were added at the sameconcentration as the primary antibody and incubated for 30 minutes.After incubation, the samples were washed and the signal was read in theBD Pathway 855 fluorescence microscope. For the activation of caspases,images were captured at 633 nm of emission and for H2AX at 594 nm.

Statistical Analysis

Each experiment was repeated at least twice. The values are given asmean±standard deviation. The data were analyzed by statistical unpairedStudent's t-test using the statistical software Statgraphics versionCenturion XVI.I (USA). P-values of less than 0.05 were considered to besignificant.

Results. Cell Viability

After a period of 3 light exposure cycles to for 12 hours, alternatingwith 3 recovery cycles for a further 12 hours, the nuclei of the primaryhuman retinal pigment epithelial cells were DAPI-stained to count thenumber of cells per well.

The non-irradiated cells grew well in the wells, but irradiation withmonochromatic LED light inhibited cell growth. Blue light (468 nm)produced a very significant reduction in the number of cells, althoughthere was also an observable phototoxic effect for green light (525 nm).In the case of white light (T°=5400° K) no statistically significantdifferences were observed.

With the presence of the blocking element of short wavelengths, anincrease of cell viability was observed, mainly in cells exposed towhite light (T°=5400° K) and light blue (468 nm) as shown in the table2.

TABLE 2 white LED (T ° = Blue LED Green LED Red LED Cell viabilityControl 5400° K) (468 nm) (525 nm) (616 nm) Without blocking 855 ± 403217 ± 108 10 ± 2 99 ± 114 339 ± 1  element (FU) With blocking 1156 ±156  346 ± 71  358 ± 20 188 ± 43  420 ± 69 element (FU) p-value 0.2120.047* 0.000* 0.102 0.096 Increase (%) — 59 3480 — —

In FIG. 4, the LED light effect and the photoprotective effect of ablocking element that selectively absorbs the short wavelengths on thecell viability in human retinal pigment epithelial cells can be seen. FUmeans fluorescence unit.

Results: DNA Damage

To examine whether the radiation had some effect on the integrity ofcellular DNA, cells were marked using H2AX antibody.

H2AX is a variant of the histone H2A that is involved in DNA repair,i.e. when there is damage in nuclear DNA. When the double-stranded DNAbreak occurs, H2AX histone is rapidly phosphorylated on serine 139 bykinase ATM and becomes Gamma-H2AFX.

This phosphorylation step can extend to several thousands of nucleosomesfrom the site of the double-strand break and can mark the surroundingchromatin in the recruitment of the proteins necessary for damagesignaling and DNA repair. As part of post-translational modifications ofapoptosis, caused by severe DNA damage, a high expression ofphosphorylated H2AX is considered as an accurate indicator of apoptosis.

The results of experiments showed that anti-H2AX antibody recognizessites of phosphorylated histones after irradiation with LED lightindicating an activation of DNA repair mechanisms.

By interposing the blocking element of the short wavelengths, asignificant decrease in activation of histone H2AX, indicative of lessDNA damage, was observed. This decrease was 97% for white (T°=5400° K),blue (468 nm), and green (525 nm) LED light, and 95% in cells exposed tored LED light, as seen in table 3.

TABLE 3 White LED (T ° = Blue LED Green LED Red LED Activation of H2AXControl 5400° K) (468 nm) (525 nm) (616 nm) Without blocking 131 ± 412697 ± 493 2537 ± 589 2258 ± 738 1920 ± 286  element (FU) With blocking47 ± 1  83 ± 20 76 ± 7  63 ± 10 91 ± 15 element (FU) p-value 0.024*0.000* 0.002* 0.001* 0.000* Decrease (%) — 97% 97% 97% 95%

In FIG. 5, the LED light effect and the photoprotective effect of ablocking element that selectively absorbs the short wavelengths on theactivation of histone H2AX in human retinal pigment epithelial cells, isshown. FU means fluorescence unit.

Results: Apoptosis

The activation of caspase-3 and -7 was determined, since these enzymesare involved in the regulation and execution of apoptosis. The cellswere marked using the anti-caspase antibody.

Irradiation with LED light in the cells caused an increase in thepercentage of apoptotic cells in the culture. The caspase activation isobserved as a pinkish color around the blue-stained nucleus (DAPI).

The interposition of the blocking element of short wavelengths induced asignificant decrease in caspase activation, indicative of apoptosis incells exposed to the different LED light sources. This decrease was 89%for white (T°=5400° K) and blue (468 nm) lights, 54% for green light(525 nm), and 76% for red light, as shown in table 4.

TABLE 4 White LED (T ° = Blue LED Green LED Red LED Activation ofcaspases Control 5400° K) (468 nm) (525 nm) (616 nm) Without blocking0.037 ± 0.02 0.888 ± 0.02 0.861 ± 0.03 0.839 ± 0.05 0.655 ± 0.07 element(FU) With blocking 0.114 ± 0.15 0.094 ± 0.03 0.094 ± 0.05 0.386 ± 0.480.155 ± 0.08 element (FU) p-value 0.541 0.000* 0.000* 0.312 0.006*Reduction (%) — 89% 89% 54% 76%

In FIG. 6, the LED light effect and photoprotective effect of a blockingelement that selectively absorbs the short wavelengths on the activationof the caspase-3, -7 in human retinal pigment epithelial cells, isshown. FU means fluorescence unit.

Following an analysis of the problem and an example of solution, thelight, especially that of smaller wavelengths, in 3 cycles of 12 hoursof exposure alternating with 12 hours of recovery, affects the growth ofthe human retinal pigment epithelial cells. An increase in the number ofcells expressing the histone H2AX (DNA damage) y caspase-3 and -7(apoptosis) occurs.

In all cases the blocking element that selectively absorbs the shortwavelengths exerts a protective effect against the damaging effects oflight on the human retinal pigment epithelial cells.

Selection of the Optical Density of Blocking Element that Absorbs theShort Wavelengths

It is obvious for a person skilled in the art that other particularembodiments can be possible, and not only that shown in the previousexample. However, all particular realizations have to take into accountthat the absorbance that blocks the wavelengths between 380 and 500 nmmust be selected, as well as reduced, via software, said emissionselectively without reducing the intensity or amount of light.

For this reason, the present invention establishes a series of factors(table 5) to which are endowed them a certain maximum and minimum weightto precisely set the maximum and minimum absorbance for each individual:

TABLE 5 Maximum Minimum Factor Degree limit (%) limit (%) Age  0-10 4 1(years) 10-20 5 2 20-40 5 2 40-60 7 4 60-75 10 8 >75 12 8 Type of useddevices Smartphones (25-40 cm) 2 1 (working distance) Tablets (25-40 cm)3 1 Computer screens 4 2 (41-70 cm) Television screens 4 2 (>70 cm)Total exposure time  <3 2 1 (hours) 3-5 3 2 5-8 4 3 8-10 5 3 >10 5 3Conditions of lowest Photopic (>5) 2 1 ambient lighting Mesopic(0.005-5) 5 2 during the use of Scotopic (<0.005) 10 4 the devices(cd/m²) Disease State Retinal disease states Mild stage 50 30 Moderatestage 60 40 Severe stage 70 50 Corneal disease states Mild stage 20 10Moderate stage 30 20 Severe stage 40 30 Palpebral disease states 5 2Conjunctival disease 5 2 states Scleral disease states 5 2 Glaucoma 2010 Pseudophakic/Aphakia 30 10

The sum of the various factors listed by way of example in table 5 iswhat gives as a result a maximum and minimum absorbance thresholdcorresponding to FIG. 2, where, by way of an example, for a user between25 years old (max. 5, min 2) that works with a computer (4/2), with anexposure time to the light source by the user less than 3 hours (2/1),with an ambient lighting of the place where the user interacts with thephotopic LED-type light source (2/1) and without disease states, isstated that we would have a maximum absorbance in the range of 380-500nm of (5+2+2+2) of 13%, while the minimum of absorbance would be 6%, asshown, for example in FIG. 2. However, if the same individual usesvarious electronic devices (computer, tablet and smartphone) for morethan 10 hours in environments of high and low lighting, the preferredabsorbance range would be between 11-24%. On the other hand, if theindividual has a moderate retinal disease state and was exposed totelevision for 3-5 hours a day in high light conditions, the recommendedabsorbance range would be 47-74%.

Some might think it is not necessary to have a maximum absorbance rangeand completely block the passage of the short wavelengths between380-500. However, the total blocking of the blue light produces effectsboth on the visibility of the screen and on the individual's circadiancycle itself, so it is logical to set a minimum and maximum absorbancerange, minimizing such negative effects.

Examples and practical embodiments to achieve this selective absorbancevary since it can be a multilayer substrate (the blocking element usedin the example), a coating (gel, foam, emulsion, solution, dilution ormixture) with a pigment of this optical density, or reduction viasoftware of the emission on the spectrum of 380-500 nm.

The portable electronic device (100) as one that can be used in thepresent invention according to some practical embodiments is shown inFIG. 7. More specifically, the portable electronic device 100 of theinvention includes a memory 102, a memory controller 104, one or moreprocessing units (CPU) 106, a peripherals interface 108, a RF circuitry112, an audio circuitry 114, a speaker 116, a microphone 118, aninput/output (I/O) subsystem 120, a LED display 126, other input orcontrol devices 128, and an external port 148. These componentscommunicate over the one or more communication buses or signal lines110. The device 100 can be any portable electronic device, including butnot limited to a handheld computer, a tablet computer, a mobile phone, amedia player, a personal digital assistant (PDA), or the like, includinga combination of two or more of these items. It should be appreciatedthat the device 100 is only one example of a portable electronic device100, and that the device 100 may have more or fewer components thanshown, or a different configuration of components. The variouscomponents shown in FIG. 1 may be implemented in hardware, software or acombination of both hardware and software, including one or more signalprocessing and/or application specific integrated circuits. In the sameway, the LED display 126 has been defined, although the invention mayalso be implemented in devices with a standard display.

The memory 102 may include high-speed random-access memory and may alsoinclude non-volatile memory, such as one or more magnetic disk storagedevices, flash memory devices, or other non-volatile solid state memorydevices. In some embodiments, the memory 102 may further include storageremotely located from the one or more processors 106, for instancenetwork attached storage accessed via the RF circuitry 112 or externalport 148 and a communications network (not shown) such as the Internet,intranet(s), Local Area Networks (LANs), Wide Local Area Networks(WLANs), Storage Area Networks (SANs) and the like, or any suitablecombination thereof. Access to the memory 102 by other components of thedevice 100, such as the CPU 106 and the peripherals interface 108, maybe controlled by the memory controller 104.

The peripherals interface 108 couples the input and output peripheralsof the device to the CPU 106 and the memory 102. The one or moreprocessors 106 run various software programs and/or sets of instructionsstored in the memory 102 to perform various functions for the device 100and to process data.

In some embodiments, the peripherals interface 108, the CPU 106, and thememory controller 104 may be implemented on a single chip, such as achip 111. In some other embodiments, they may be implemented on separatechips.

The RF (radio frequency) circuitry 112 receives and sendselectromagnetic waves. The RF circuitry 112 converts electrical signalsto/from electromagnetic waves and communicates with communicationsnetworks and other communications devices via the electromagnetic waves.The RF circuitry 112 may include well-known circuitry for performingthese functions, including but not limited to an antenna system, an RFtransceiver, one or more amplifiers, a tuner, one or more oscillators, adigital signal processor, a CODEC chipset, a subscriber identity module(SIM) card, memory, and so forth. The RF circuitry 112 may communicatewith the networks, such as the Internet, also referred to as the WorldWide Web (WWW), an Intranet and/or a wireless network, such as acellular telephone network, a wireless local area network (LAN) and/or ametropolitan area network (MAN), and other devices by wirelesscommunication. The wireless communication may use any of a plurality ofcommunications standards, protocols and technologies, including but notlimited to Global System for Mobile Communications (GSM), Enhanced DataGSM Environment (EDGE), wideband code division multiple access (W-CDMA),code division multiple access (CDMA), time division multiple access(TDMA), Bluetooth, Wireless Fidelity (Wi-Fi) (e.g., IEEE 802.11a, IEEE802.11b, IEEE 802.11g and/or IEEE 802.11n), voice over Internet Protocol(VoIP), Wi-MAX, a protocol for email, instant messaging, and/or ShortMessage Service (SMS), or any other suitable communication protocol,including communication protocols not yet developed as of the filingdate of this document.

The audio circuitry 114, the speaker 116, and the microphone 118 providean audio interface between a user and the device 100. The audiocircuitry 114 receives audio data from the peripherals interface 108,converts the audio data to an electrical signal, and transmits theelectrical signal to the speaker 116. The speaker converts theelectrical signal to human-audible sound waves. The audio circuitry 114also receives electrical signals converted by the microphone 116 fromsound waves. The audio circuitry 114 converts the electrical signal toaudio data and transmits the audio data to the peripherals interface 108for processing. Audio data may be may be retrieved from and/ortransmitted to the memory 102 and/or the RF circuitry 112 by theperipherals interface 108. In some embodiments, the audio circuitry 114also includes a headset jack (not shown). The headset jack provides aninterface between the audio circuitry 114 and removable audioinput/output peripherals, such as output-only headphones or a headsetwith both output (headphone for one or both ears) and input(microphone).

The I/O subsystem 120 provides the interface between input/outputperipherals on the device 100, such as the LED display 126 and otherinput/control devices 128, and the peripherals interface 108. The I/Osubsystem 120 includes a LED-display controller 122 and one or moreinput controllers 124 for other input or control devices. The one ormore input controllers 124 receive/send electrical signals from/to otherinput or control devices 128. The other input/control devices 128 mayinclude physical buttons (e.g., push buttons, rocker buttons, etc.),dials, slider switches, and/or geographical location means 201, such asGPS or similar.

In this practical embodiment, the LED display 126 provides both anoutput interface and an input interface between the device and a user.The LED-display controller 122 receives/sends electrical signals from/tothe LED display 126. The LED display 126 displays visual output to theuser. The visual output may include text, graphics, video, and anycombination thereof. Some or all of the visual output may correspond touser-interface objects, further details of which are described below.

The LED display 126 also accepts input from the user based on hapticcontact. The LED display 126 forms a touch-sensitive surface thataccepts user input. The LED display 126 and the LED-display controller122 (along with any associated modules and/or sets of instructions inthe memory 102) detects contact (and any movement or break of thecontact) on the LED display 126 and converts the detected contact intointeraction with user-interface objects, such as one or more soft keys,that are displayed on the LED display. In an exemplary embodiment, apoint of contact between the LED display 126 and the user corresponds toone or more digits of the user.

The LED display 126 is or may be formed by a plurality of light-emitterdiodes, and more specifically formed by white LEDs, although other typeof LED emitters may be used in other embodiments.

The LED display 126 and LED-display controller 122 may detect contactand any movement or break thereof using any of a plurality of touchsensitivity technologies, including but not limited to capacitive,resistive, infrared, and surface acoustic wave technologies, as well asother proximity sensor arrays or other elements for determining one ormore points of contact with the LED display 126.

The device 100 also includes a power system 130 for powering the variouscomponents. The power system 130 may include a power management system,one or more power sources (e.g., battery, alternating current (AC)), arecharging system, a power failure detection circuit, a power converteror inverter, a power status indicator (e.g., a light-emitting diode(LED)) and any other components associated with the generation,management and distribution of power in portable devices.

In some embodiments, the software components include an operating system132, a communication module (or set of instructions) 134, acontact/motion module (or set of instructions) 138, a graphics module(or set of instructions) 140, a user interface state module (or set ofinstructions) 144, and one or more applications (or set of instructions)146.

The operating system 132 (e.g., Darwin, RTXC, LINUX, UNIX, OS X,WINDOWS, or an embedded operating system such as VxWorks) includesvarious software components and/or drivers for controlling and managinggeneral system tasks (e.g., memory management, storage device control,power management, etc.) and facilitates communication between varioushardware and software components.

The communication module 134 facilitates communication with otherdevices over one or more external ports 148 and also includes varioussoftware components for handling data received by the RF circuitry 112and/or the external port 148. The external port 148 (e.g., UniversalSerial Bus (USB), FIREWIRE, etc.) is adapted for coupling directly toother devices or indirectly over a network (e.g., the Internet, wirelessLAN, etc.).

The contact/motion module 138 detects contact with the LED display 126,in conjunction with the LED-display controller 122. The contact/motionmodule 138 includes various software components for performing variousoperations related to detection of contact with the LED display 122,such as determining if contact has occurred, determining if there ismovement of the contact and tracking the movement across the LEDdisplay, and determining if the contact has been broken (i.e., if thecontact has ceased). Determining movement of the point of contact mayinclude determining speed (magnitude), velocity (magnitude anddirection), and/or an acceleration (including magnitude and/ordirection) of the point of contact. In some embodiments, thecontact/motion module 126 and the LED display controller 122 alsodetects contact on the LED pad.

The graphics module 140 includes various known software components forrendering and displaying graphics on the LED display 126. Note that theterm “graphics” includes any object that can be displayed to a user,including without limitation text, web pages, icons (such asuser-interface objects including soft keys), digital images, videos,animations and the like.

In some embodiments, the graphics module 140 includes an opticalintensity module 142. The optical intensity module 142 controls theoptical intensity of graphical objects, such as user-interface objects,displayed on the LED display 126. Controlling the optical intensity mayinclude increasing or decreasing the optical intensity of a graphicalobject. In some embodiments, the increase or decrease may followpredefined functions.

The user interface state module 144 controls the user interface state ofthe device 100. The user interface state module 144 may include a lockmodule 150 and an unlock module 152. The lock module detectssatisfaction of any of one or more conditions to transition the device100 to a user-interface lock state and to transition the device 100 tothe lock state. The unlock module detects satisfaction of any of one ormore conditions to transition the device to a user-interface unlockstate and to transition the device 100 to the unlock state.

The one or more applications 130 can include any applications installedon the device 100, including without limitation, a browser, addressbook, contact list, email, instant messaging, word processing, keyboardemulation, widgets, JAVA-enabled applications, encryption, digitalrights management, voice recognition, voice replication, locationdetermination capability (such as that provided by the globalpositioning system (GPS)), a music player (which plays back recordedmusic stored in one or more files, such as MP3 or AAC files), etc.

In some embodiments, the device 100 may include one or more optionaloptical sensors (not shown), such as CMOS or CCD image sensors, for usein imaging applications.

Thus, the portable electronic device (100) essentially comprises, a LEDdisplay (126); one or more processors (106); a memory (102); and one ormore programs wherein the program(s) (132 to 146) are stored in thememory (102) and configured to be executed by at least the processor(s)(106), the programs (132 to 146) including instructions to calculate theemissions of harmful short wavelengths between 380 and 500 nm andselectively reducing the emission of short wavelengths between 380-500nm of at least a portion of the LEDs contained in the display (126). Allof this as has already been indicated above.

The selective reduction is carried out by modifying the colors in theoperating system (134) or in the color intensity module (142). In anycase, there is also the possibility that said selective reduction istemporarily progressive so that the greater exposure time to the screen(126) of device (100), the greater reduction will be.

Finally, the computer program product with instructions configured forexecution by one or more processors (106) that, when executing by aportable electronic device (100) as describe, said device (100) carriesout the method according to the computer-implemented method to block theshort wavelengths in LED-type light sources characterized in that itcomprises the steps of: (i) calculating the emissions of harmful shortwavelengths between 380 and 500 nm; and (ii) selectively reducing theemission of short wavelengths between 380-500 nm of the LEDs containedin the display depending on the calculation set out in the step (i).

The calculation of the harmful emissions is a function of at least oneof the following variables: age of a user of LED-type light source,separation distance to the LED-type light source, size of the LED-typelight source, exposure time to the light source by the user, ambientlighting of the place where the user interacts with the LED-type lightsource and the possible retinal and/or corneal disease state.

This computer program product can be physically implemented in thedisplay hardware itself or in the video controller of a computer systemcomprising a LED-type display.

The protection of the retina, cornea and crystalline of the harmfulaction of the short wavelengths, as well as the elimination of theeyestrain, the improvement of the comfort and visual function, and theavoidance of the insomnia, final objects of the invention, are alsoachieved both with the computer-implemented method and with the portableelectronic device (100), and with the described computer product.

One of the possibilities given by the invention is the possibility ofchanging the background of any document to one less aggressive for thehuman eye. Indeed, today, most of the documents have a white background,while its content is typically in a color that offers a strong contrast,like black, blue, red or green. This is conditioned by the fact thatelectronic documents, in general, try to imitate the documents writtenon paper, in addition to minimize the cost of printing of saiddocuments.

However, that contrast, as described, implies a strong light emissionwith a harmful content for the human eye. Therefore, and thanks to thedescribed method, the computer-implemented method, the device, and thecomputer product implement a further step of detecting the background ofthe document shown to the user, and a second step of switching saidbackground to one with a reduced emission on the spectrum indicated.

Test of Lighting Characterization of Portable Electronic Devices of theType of Tablets with LED Backlit Displays.

In order to justify the convenience of the invention, a test of lightingcharacterization of several tablets in the market and LED-backlit hasbeen implemented.

The following concepts are defined in the test:

Emission spectrum is the set of frequencies of the electromagnetic wavesthat are obtained by breaking down the radiation emitted by the lightsource.

Irradiance (mW/cm2): Radiometric magnitude used to describe the incidentpower per unit area of all types of electromagnetic radiation.

The aim of the test is to determine the lighting characteristics of 3display of tablets with LED backlight which project different images ontheir display:

a) Determine the emission spectrum of the light sourcesb) Determine the irradiance of the light sourcesc) Calculate the irradiance for every wavelength from the measurement ofthe emission spectrum of the display and the total irradiance.

The measures were performed on the models Apple IPad 4, Asus Memo PadSmart y Samsung Galaxy Tab 10.1 (all trademarks registered by theirrespective owners) for a total of 22 wallpapers of different colors. The3 primary colors (red, green and blue) were used, to which variations ofhue and saturation were performed. Likewise the measures were performedwith a white background. The following table set out the hue, saturationand brightness of each of the colors of the image projected on thedisplay of the tablets that have been assessed:

TABLE 6 Hue Saturation Brightness Red Green Blue Pure Red 0 240 120 2550 0 Red 1 3 240 120 255 19 0 Red 2 5 240 120 255 32 0 Red 3 7 240 120255 45 0 Red A 0 220 120 244 11 11 Red B 0 200 120 234 21 21 Red C 0 180120 223 32 32 Pure Green 80 240 120 0 255 0 Green 1 83 240 120 0 255 19Green 2 85 240 120 0 255 32 Green 3 87 240 120 0 255 45 Green A 80 220120 11 244 11 Green B 80 200 120 21 234 21 Green C 80 180 120 32 223 32Pure Blue 160 240 120 0 0 255 Blue 1 163 240 120 19 0 255 Blue 2 165 240120 32 0 255 Blue 3 167 240 120 45 0 255 Blue A 160 220 120 11 11 244Blue B 160 200 120 21 21 234 Blue C 160 180 120 32 32 223 White 160 0240 255 255 255

To determine the emission spectrum of the LED light sources was used theOcean Optics Redtide USB 650 spectrophotometer. The data were analyzedusing the Ocean Optics SpectraSuite software and plotted using theSigmaplot software.

The acquisition protocol used for acquisition of measurements was:

Exposure time: 200 milliseconds

No. of scans of intensity: 5 (Each measurement of intensity emission isobtained from an average of 5 measurements carried out by theinstrument).

The total irradiance of the light sources was determined with a ThorlabsPM100USB radiometer at a distance of 35 cm.

For the calculation of irradiance according to its wavelength, thefollowing mathematical analysis was carried out:

${I(\lambda)} = {I_{T}\frac{E(\lambda)}{E_{T}}}$

Where:

I(λ) is the irradiance depending on the wavelength.I_(T) is the total irradiance measured in the experimental procedure.E(λ) is the relative electromagnetic spectrum depending on thewavelength measured in the experimental procedure.E_(T) is the is the total electromagnetic spectrum measured in theexperimental procedure.

Test Results for the Model Asus Memo Pad Smart

In the graph shown in FIG. 8A, the irradiance (mW/cm²) depending on thewavelength of the tablet Asus Memo Pad Smart, using as a background theprimary colors (red, green and blue) and a white image, is represented.In FIG. 8 and the subsequent graphs, the variation in lightingcharacteristics of the tablet display due to a change in the hue (FIG.8B) or the saturation of the image of each of the primary colors (FIG.8C) is represented.

On the other hand in FIG. 8D, the irradiance (mW/cm²) depending on thewavelength de la tablet Asus Memo Pad Smart with and without theinterposition of a protective filter which partially absorbs the shortwavelengths of the visible spectrum, according to the object of theinvention, is represented. In table 7, the represented values areindicated:

TABLE 7 Absorption of the wavelength (nm) filter (%) 410 18 415 24 42028 425 23 430 23 435 24 440 23 445 24 450 20 455 17 460 15 465 14 470 15475 12 480 12 485 10 490 11 495 12 500 10Test Results for the Model Apple iPad 4

In the graphs in FIG. 9, the irradiance (mW/cm²) depending on thewavelength of the tablet iPad 4, using as a background the primarycolors (red, green and blue) and a white image (FIG. 9A), isrepresented.

In the subsequent graphs, the variation in lighting characteristics ofthe tablet display due to a change in the hue (FIG. 9B) or thesaturation of the image of each of the primary colors (FIG. 9C), isrepresented.

On the other hand in FIG. 9D, the irradiance (mW/cm²) depending on thewavelength of the tablet iPad 4 with and without the interposition of aprotective filter which partially absorbs the short wavelengths of thevisible spectrum, according to the object of the invention, isrepresented. In table 8, the represented values are indicated:

TABLE 8 Absorption of the wavelength (nm) filter (%) 410 22 415 14 42015 425 21 430 22 435 22 440 19 445 20 450 20 455 17 460 15 465 13 470 14475 12 480 13 485 9 490 11 495 11 500 11

Test Results for the Model Samsung Galaxy Tab 10.1

In the graphs in FIG. 10, the irradiance (mW/cm²) depending on thewavelength of the tablet Samsung Galaxy Tab 10.1, using as a backgroundthe primary colors (red, green and blue) and a white image (FIG. 10A),is represented.

In the subsequent graphs, the variation in lighting characteristics ofthe tablet display due to a change in the hue (FIG. 10B) or thesaturation of the image of each of the primary colors (FIG. 10C) isrepresented.

On the other hand in FIG. 10D, the irradiance (mW/cm²) depending on thewavelength of the tablet Samsung Galaxy Tab 10.1 with and without theinterposition of a protective filter which partially absorbs the shortwavelengths of the visible spectrum, according to the object of theinvention, is represented. In table 9, the represented values areindicated:

TABLE 9 Absorption of the wavelength (nm) filter (%) 410 11 415 14 42029 425 28 430 20 435 22 440 23 445 17 450 15 455 17 460 13 465 10 470 11475 9 480 8 485 10 490 10 495 5 500 7

According to the results reported in all the previous tests, it isproved that the reduction in emission caused by LED-type displays on thespectrum between the 380-500 nm is beneficial and can be easilycorrected also via hardware and software.

1-19. (canceled)
 20. A blocking element of short wavelengths in LED-type light sources comprising: a substrate with a pigment distributed on its surface wherein the pigment has an optical density such that it allows the selective absorption of light emission in LED-type light sources between a maximum percent of absorption and a minimum percent of absorption of the short wavelengths between 380 nm and 500 nm without completely blocking passage of wavelengths between 380 nm and 500 nm, and wherein the maximum percent of absorption and the minimum percent of absorption are the sum of a maximum percent of absorption and a minimum percent of absorption selected from a predetermined maximum and minimum absorption values of at least one of the following factors: the age of a user of LED-type light source, the size of the LED-type light source, the total exposure time of a user to the LED-type light source, the ambient lighting of the place where the user interacts with the LED-type light source, the time of day, the type of LED-type light source, or a retinal or corneal disease state of the user.
 21. The blocking element according to claim 20 comprising a multilayer substrate wherein at least one of said layers contains the blocking pigment of short wavelengths distributed over the surface of said layer.
 22. The blocking element of short wavelengths according to claim 20 wherein the substrate is a coating containing a pigment in the entire coating.
 23. The blocking element of short wavelengths according to claim 22 wherein the coating is one selected from gel, foam, emulsion, solution, dilution, or a combination of the above.
 24. The blocking element according to claim 20 wherein the pigment is evenly distributed over the surface of the substrate.
 25. A blocking method of short wavelengths in LED-type light sources characterized in that it comprises the steps of: selecting a mean optical density of a pigment between a maximum percent of absorption and a minimum percent of absorption in the range of short wavelengths between 380 nm and 500 nm; and pigmenting a substrate over its entire surface in such a way that the mean absorption is between said maximum and minimum percent of absorption without completely blocking passage of wavelengths between 380 nm and 500 nm; and wherein the maximum percent of absorption and the minimum percent of absorption is the sum of a maximum percent of absorption and a minimum percent of absorption selected from a predetermined maximum and minimum absorption values of at least one of the following factors: the age of a user of LED-type light source, the size of the LED-type light source, the total exposure time of a user to the LED-type light source, the ambient lighting of the place where the user interacts with the LED-type light source, the type of LED-type light source, or a retinal or corneal disease state of the user.
 26. The method according to claim 25 where the pigment is evenly distributed over the surface of the substrate.
 27. A LED display comprising the blocking element of short wavelengths according to claim
 20. 28. A LED display obtained by a manufacturing process comprising a step of applying the method of claim
 25. 